Percussive apparatus



1948- c. A. HIRSCHBERG 2,446,830

PERCUSS IVE APPARATUS Filed March 2, 1945 2 Sheets-Sheet l INVENTOR.62w! A. Ez'nsdlezy,

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- Alta 717g 1948- c. A. HIRSCHBERG 2,446,830

PERCUSSIVE APPARATUS INVENTOR. CJarles Afihscffiez' Patented Aug. 19,1948 NlTED STATES TENT OFFICE 3 Claims. 1

This invention relates to improvements in percussive apparatus such asrock drills, automatic hammers, and like impact producing mechanisms,whereby the means for imparting impact upon the drill steel or othertool to be actuated is of the explosive or internal combustion enginetype.

The invention has for an object to provide a percussive apparatus of thekind above referred .to comprising an impact delivering means slidablyreciprocable in a cylinder, with the upper portion of said means and ofsaid cylinder operating to provide the piston and explosive chamber ofan internal combustion engine, a crank-shaft having a fly-wheel, andsaid impact delivering means being provided with novel axially alignedmeans adapted to so cooperate with said crank-shaft that the latter isautomatically connected and disconnected with said impact deliveringmeans in timed relation to the power stroke thereof, whereby the initialphase of said power stroke is utilized to actuate the fly-wheel. theimpact delivering means being thereupon freed to complete itspowerstroke unimpeded by the crank-shaft, and finally whereby the inertia ofmotion of the fly-wheel reengages the crankshaft with the impactdelivering means to effect the return or recovery stroke thereof; thealigned relation of said crank-shaft engageable means with the centrallongitudinal axis of the impact delivering means being adapted to avoidtransmission of side thrust to the latter, thus reducing frictionalresistance to its reciprocable movements to a minimum.

Another object of this invention is to provide in percussive apparatusof the kind referred to an internal combustion engine means of the twocycle type for producing the power stroke of the impact deliveringmeans, wherein the cylinder and piston structure is of compound formcomprising a main piston operative in the explosion chamber of thecylinder and a diametrically enlarged secondary piston operative in acorrespondingly enlarged fuel mixture induction chamber of saidcylinder, means being provided for delivering a fuel mixture to saidinduction chamber, and means being provided for transferring the fuelmixture from said induction chamber to the explosion chamber of thecylinder.

Other objects of this invention, not at this time more particularlyenumerated, will be understood from the following detailed descriptionof the same.

An illustrative embodiment of the invention is shown in the accompanyingdrawings, in which:

Fig. 1 is a longitudinal sectional View of percussive apparatusaccording to this invention, the impact delivering means being shown inelevation, and at the top of its recovery stroke; Fig. 2 is a similarview, with parts broken away, and showing the impact delivering means atthe end of its power stroke; Figs. 3 and 4 are similar fragmentaryviews, respectively showing progressive phases of the crank-shaftmovement operative to effect a recovery or return stroke of the impactdelivering means; and Fig. 5 is a longitudinal sectional view, taken online 5-5 in Fig. 1, parts being broken away.

Similar characters of reference are employed in the above describedviews, to indicate corresponding parts.

Referring to the drawings, the reference characters i9 and IIrespectively indicate upper and lower sections of a cylinder, which aresuitably connected together in axially aligned, end to end relation.

The top part of the upper cylinder section In is provided witha bore ofsuitable diameter, whereby to form an eXplosion chamber l2. The top endof said explosion chamber i2 is closed by a cylin-, der head l3, whichissuitably secured to the top end of said upper cylinder section lllThat portion of the walls of said upper cylinder section 10 which boundthe explosion chamber I2 may be cored to provide internal spaces orpassages lli through which a cooling fluid may be circulated, if sodesired. Below the explosion chamber i2, said upper cylinder section inis provided with a second bore of enlarged diameter and suitable length,whereby to provide a fuel mixture induction chamber l5. upper cylindersection Hi and the entire length of the lower cylinder section If isprovided with a bore l6 which is preferably, but not necessarily,

somewhat larger in diameter than that of the.

fuel mixture induction chamber l5. Said bore It provides a slideway forthe guide piston portion of the impact delivering means of the apparatus hereinafter described.

The impact delivering means of the apparatus is slidably reciprocablewithin the above described cylinder structure and comprises a unitarystructure provided at its upper end with an engine piston l'l adapted toslidably fit the explosion chamber 12 so as to reciprocate therein.Spaced from and below said engine piston i7 is a fuel mixture controlpiston l8 adapted to slidably fit the fuel mixture induction chamber l5so as to reciprocate therein. Said fuel mixture control piston I8 isconnected with the engine piston 11 by an intermediate axial shankportion I9 of substantially.

The lower part of said reduced diameter; being smaller in diameter thansaid engine and control pistons. At its lower end, the impact deliveringmeans is provided with a guide piston 20 adapted to slidably fit thebore I6 of the cylinder structure so as to reciprocate therein.Extending between said fuel mixture control piston I8 and said guidepiston 20 is a cam-frame 2| of suitable width, the same being disposedin a transverse plane intersecting the longitudinal axis of the impactdelivering means. The upper end of said cam-frame is unitarily connectedwith the fuel mixture control piston I8 by an upper neck portion 22. Thelower end of said cam-frame is unitarily connected with the guide piston20 by a lower neck portion 23. Said cam-frame is provided with acircular opening which defines a lift cam member 24. Leadingtangentially from said opening, so as to extend outwardly and upwardlytherefrom is an extension of said opening adapted to provide alongitudinal slideway 25.

The cylinder structure is provided at opposite sides thereof withbearing portions 26 which are aligned on a transverse axis extending atright angles to the plane of said cam-frame 2 I. Jour-- naled in andbetween said bearing portions 26 is a crank-shaft 2'1. Said crank-shaftis provided with spaced crank-arms 28 adapted to straddle the cam-frame2|. Extending between the outward ends of said crank-arms 28 is acrank-pin 29 upon which is mounted suitable anti-friction means 30. Saidcrank-pin 29 and its anti-friction means 30 extends through the openingof said cam-frame 2|, whereby to cooperate with the lift cam member 24of the latter. Said crankshaft is provided with an outer end portion 3|arranged to extend exteriorly from the cylinder structure, and fixed onsaid outer end portion 3| is a fly-wheel 32.

Connected with the upper section II] the cylinder structure is means foradmitting a fuel mixture into the fuel induction chamber I5. This meanscomprises a valve casing 33 having a passage 34 terminating in an inletport 35 which communicates with the interior of the fuel inductionchamber I5. Said inlet port 35 is normally closed by an inwardly openingspring closed valve 36. Connected with the intake end of the valvecasing passage 34 is a fuel mixture delivery conduit 3'! which leadsfrom a suitable carburetor device (not shown).

Also connected with the upper section I of the cylinder structure ismeans for transferring a fuel mixture from the induction chamber I tothe explosion chamber I2. This means comprises a by-pass housing 38having an outlet port 39 leading from the interior of said fuelinduction chamber I5 to a valve chamber 40. Said outlet port is normallyclosed by an outwardly opening spring closed valve 4|. Said valvechamber 40 communicates with a fuel mixture receiving chamber 42. Saidreceiving chamber 42 communicates with the explosion chamber I2 througha fuel admission port 43.. Said admission port 43 is closed by theengine piston II, but is opened temporarily when the top end of saidengine piston II passes the same as said engine piston, in descending.completes its down or power stroke. The upper section of the cylinderstructure is provided, in a side thereof opposite to that at which saidadmission port 43 is located, with an exhaust port 44; said exhaust portbeing likewise located so as to be opened temporarily when the top endof the engine piston I! passes the same as said engine piston, indescending, completes its down or power stroke. Suitably arranged toenter the explosion chamber I2 is a spark plug 45, which is adapted tobe electrically controlled and operated in a manner well known; or anyother suitable form of explosive charge ignition means may be provided.

The lower section II of the cylinder structure terminates in a toolreceiving member 45 having a suitably shaped and bushed throat member 41provided with an axial passage 48 to receive the shank end portion 49 ofa drill steel 50 or other impact operated tool. Projecting downwardlyfrom the guide piston 20 is an axially aligned striking member 5|adapted to be reciprocated with the impact delivering means of theapparatus, whereby, upon operation of the latter, to intermittentlystrike the steel or tool with forceful driving blows.

Connected with the free end of the tool receiving member 46 is a drillor tool retaining and aligning means, which may optionally comprise amanipulatable coupler body structure 52 of the kind fully disclosed inmy copending application for Letters Patent Ser. No. 553,164, filedSeptember 8, 1944, now Patent No. 2,430,716, or one of any other knowntype.

In operation of the apparatus, on a down-stroke of the fuel mixturecontrol piston I8, a reduction of pressure occurs in the inductionchamber I5 so that the valve 36 is caused to open, thus drawing from thedelivery conduit 31 and through the valve casing passage 34 the fuelmixture from the supply thereof, and admitting the same into theinduction chamber I5 through the opened inlet port 35. On an up-strokeof the piston I8, the valve 36 closes the inlet port 35, and the fuelmixture within the induction chamber I5 is, by compression, drivenoutwardly therefrom through the outlet 39. The pressure of the outgoingfuel mixture opens the valve M, and admits the fuel mixture to thereceiving chamber 42. Since the piston I8 and the engine piston I! areunitary and move together, the rising movement of the engine pistoncloses the fuel admission port 43 which leads from the receiving chamber42 into the explosion chamber I2 of the cylinder structure (see Fig. 1),and consequently the fuel charge, delivered into the receiving chamber42 by the rising movement of piston I8, is trapped and temporarily heldin said receiving chamber, pending a succeeding descent or power strokeof the engine piston I'l induced by the firing of a previously admittedfuel charge compressed within the explosion chamber I2 during theaforesaid rising movement of said engine piston. As the engine piston I!completes its descending or power stroke movement, it passes and therebyopens both the exhaust port 44 and the fuel admission port 43 (see Fig.2), thereupon the fuel mixture charge previously stored in the receivingchamber 42 rushes into the explosion chamber I2 and displaces the spentgases of combustion by discharging the same through the exhaust port 44.The above described sequence of operations is successively repeated,whereby the apparatus is provided with a power producing agency of thetwo-cycle internal combustion engine type.

As viewed in Figs. 1 to 4 inclusive of the drawings, the crank-shaft 2'!and fly-wheel 32 are arranged to rotate in anti-clockwise direction.Since the cam-frame 2| is unitary with the described engine pistons, soas to reciprocate in company therewith, when said cam-frame 2I andengine pistons reach the limit of up-stroke movement, the crank-pin 29reaches and somewhat passes the limit of its up-swinging' movement, andis moving toward the slideway 25 of the camframe 2!, but has not clearedor moved out of contact with the lift cam member 24 of said camframe.The firing of an explosive charge within the explosion chamber 52 istimed to occur when said parts are in such relation, whereupon theresulting explosion in the explosion chamber drives downward the enginepistons so as to effect a power stroke thereof, and thereby transmittinga down-thrust to said cam-frame 2| connected therewith. Such down-thrustof the cam-frame exerts a like power transmitted down-thrust or kick tothe crank-pin 29 and crank-arm 28, thus transmitting to the crank-shaft2'5 and fly-wheel 32, a rotating impulse operative to renew inertia ofmotion thereof. After receiving such thrust or kick, the crank-pin 29moves into alignment with the slideway 25 of said cam-frame 2 i, therebyallowing the impact delivering means to move freely downward in thecylinder structure, unimpeded or unhampered by the crank-shaft 27. Theimpact delivering means being thus freed during the completion of itspower stroke, its descent is only limited by contact of the strikingmember 5! thereof with the drill steel or tool 49-50, and consequently apower induced impact of said striking member upon the latter deliversthereto an operating blow of considerable force.

While the impact delivering means is completing its power induceddescent, the inertia of movement of the revolving fly-wheel 32 continuesthe revolution of the crank-shaft 21!, whereby to complete thedown-swinging movement of the crank-pin 29, and thereupon cause the sameto enter upon its up-swinging movement, so that by the time the impactdelivering means reacts from the blow transmitted thereby to thedrillsteel or tool, the ascending crank-pin 29 will meet and engage thelift cam member 24 of said camframe (see Fig. 3). After the crank-pin 29engages the cam-member 24, continued ascent of the former in contactwith the latter under the inertia of movement of the fly-wheel 32, willexert an up-moving effect upon the impact delivering means (see Fig. 4),until up-stroke thereof is completed and the above described cycle ofoperations is repeated.

It will be observed that the cam-frame 2i and the cooperating crankmeans of the crank-shaft 21 are centrally aligned between opposite sidesof the cylinder structure, and thus in axial alignment with thereciprocable impact delivering means of the apparatus. As a consequenceof this the up-thrust transmitted by the crankshaft through thecam-frame to the piston members of the impact delivering means iscentrally applied along the axis of the piston members, whereby sidethrust is eliminated and cant-ing or tilting of the piston members isavoided. By reason of this, undue frictional resistance to longitudinalmovement of the impact delivery means is avoided, and wearing of thecylinder structure walls and piston member sides out of true issubstantially reduced if not entirely prevented. This is a factorcontributing greatly to smooth action of the apparatus in use, as wellas prolongation of its useful life.

It will be further observed, that the described construction provides avery compact, simple and highly efiicient percussive apparatus of thetype wherein the power generating agency is of the internal combustionengine type.

Having now described my invention, I claim:

1. In percussive apparatus having a power 6. generating agency of theinternalcombustion enginetype, a cylinder structure the upper portion ofwhich constitutes an explosion chamber, a unitary impact deliveringmeans re'ciprocable' iin said cylinder structure comprising enginepiston means movable in said explosion chamher, a guide piston movablein the lower portion said cylinder structure, a cam-framecentrallyaligned between opposite sides of the cylinder structureintermediate and in axial alignment with said engine piston means andsaid guide piston, and a striking member unitary with projecting axiallydownwardly .from said e piston, said cam-frame having a circular H218,the perimeter of which provides a lift cam member, and a slidewayleading tangentially upward from said opening parallel to thelongitudinal axis of the impact delivering means, reby to permit freemovement of the latter during the end phase of its operative stroke, acrank-shait journaled across said cylinder structure, the crank-pin ofsaid crank-shaft extending through said cam-frame opening and beingcooperative with the cam member formed by the perimeter of the latter, afly-wheel affixed to an exterior end of said crank-shaft, and means atthe lower end of said cylinder structure to hold a tool to be actuatedin the path of and subject to the impact of said striking member.

2. In percussive apparatus having a power generating agency of theinternal combustion engine type, a cylinder structure having an upperportion of reduced cross-sectional area to provide an explosion chamberhaving a fuel mixture admission port and an exhaust port, said cylinderstructure having a portion of relatively enlarged internalcross-sectional area immediately below said explosion chamber adapted toprovide a fuel mixture induction chamber, valved fuel mixture admissionmeans communicating with said induction chamber, valved fuel mixtureoutlet means leading from said induction chamber, a fuel mixturereceiving chamber in communication respectively with said outlet meansand the admission port of said explosion chamber, in which a fuel chargeis temporarily stored and compressed, a unitary impact delivering meansreciprocable within said cylinder structure comprising an engine pistonmovable in said explosion chamber, a fuel mixture control piston movablein said induction chamber, a guide piston movable in the lower portionof said cylinder structure, a cam-frame centrally aligned betweenopposite sides of the cylinder structure intermediate and in axialalignment with said fuel mixture control piston and said guide piston,and a striking member unitary with and projecting axially downwardlyfrom said guide piston, said cam-frame having a circular opening, theperimeter of which provides a lift cam member, and a slideway leadingtangentially upward from said opening parallel to the longitudinal axisof the impact delivering means, whereby to permit free movement of thelatter during the end phase of its operative stroke, a crank-shaftjournaled across said cylinder structure, the crank-pin of saidcrank-shaft extending through said cam-frame opening and beingcooperative with the cam member formed by the perimeter of the latter, afiy-wheel affixed to an exterior end of said crank-shaft, and means atthe lower end of said cylinder structure to hold a tool to be actuatedin the path of and subject to the impact of said striking member.

3. In percussive apparatus having a power generating agency of theinternal combustion engine type, a cylinder structure the upper portionof which is of stepped bore to provide an upper explosion chamber and alower fuel mixture induction chamber, means to admit a fuel mixture intosaid induction chamber, means to by-pass fuel mixture from saidinduction chamher to said explosion chamber, a unitary impact deliveringmeans reciprocable within said cylinder structure comprising a compoundengine piston means movable in said explosion and induction chambers, aguide piston movable in the lower portion of said cylinder structure, acamframe centrally aligned between opposite sides of the cylinderstructure intermediate and in axial alignment with said engine pistonmeans and said guide piston, and a striking member unitary with andprojecting axially downwardly from said guide piston, said cam-framehaving a circular opening, the perimeter of which provides a lift cammember, and a slideway leading tangentially upward from said openingparallel to the longitudinal axis of the impact delivering REFERENCESCITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 20 Number Name Date 1,642,949 Gilman Sept. 20,1927 1,977,645 Roberts Oct, 23, 1934 2,333,419 Fitch NOV. 2, 1943

